After getting some critics for hardwiring standard PC
serial port addresses for console / KGDB use I changed
the parameter setting once more.
The "CONSDEVNAME" kernel config option now takes
only the device name (not the unit number).
For example, for a serial console, use
options "CONSDEVNAME=\"com\""
The port address defaults to 0x3f8 (first standard serial port).
It can be changed by "CONADDR".
Similar changes apply to KGDB.
"i386/conf/GENERIC" contains updated examples.

The ISA multiport serial drivers (ast, boca, rtfps) seem broken
to me as far as console use is concerned. Has anybody used
such a thing as console successfully?

best regards
Matthias